[css-tables] Remove column collapsing from experimental

It's no longer in *active* development but it's a good feature and we
hope to get back to it.

Marked all the tests as Failure.

Bug: 174167

Change-Id: I9ec257a2ac644ccc8588043c63c796aa8185094b
Reviewed-on: https://chromium-review.googlesource.com/1208432
Commit-Queue: David Grogan <dgrogan@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589015}
2 files changed